https://www.cas.cn/syky/202603/t20260309_5103602.shtml

https://www.sciencedirect.com/science/article/abs/pii/S0167779925005517

Traditional organic acid fermentation processes require the addition of neutralizing agents to maintain a near-neutral pH production environment, but this leads to the generation of large amounts of gypsum waste during subsequent purification and extraction.

Researchers at the CAS Institute of Microbiology, have screened a *Pichia pastoris* strain from baijiu (Chinese liquor) brewing resources. This strain can grow rapidly in a culture environment with an initial glucose concentration >200 g/L and pH <3.0, making it an ideal chassis cell for organic acid fermentation. Through metabolic engineering, the research team developed an L-lactic acid fermentation process that does not require a neutralizing agent and systematically elucidated the application potential and development prospects of unconventional yeasts in the field of organic acid biomanufacturing.

For industrial application of this process, the team developed a low-cost inorganic salt culture medium, with yeast extract at only 0.03 g/L. The process reduced carbon dioxide emissions from 20% to 7.4%, and increased the carbon allocation efficiency to L-lactic acid to 91 %, achieving highly efficient utilization of the carbon source.A